Meeting Abstract

S11-2.3  Monday, Jan. 7  The advantages of gynodioecy vs. dioecy in plants CASE, A.L.*; Kent State University acase@kent.edu

Plants exhibit the full spectrum of variation in both gender expression and sexual systems. Individuals can be male, female, simultaneous hermaphrodites, or sequential hermaphrodites. Populations can be comprised of any combination of these sexes, making plants an ideal system in which to study the relative advantages and disadvantages of each alternative strategy. Indeed, evolutionary transitions between sexual systems have received more attention in plants compared to other eukaryotes, both because of their extensive sexual variability and because several features of plant life histories–including immobility and modularity–make them remarkable subjects for evolutionary and ecological research. In this talk, I summarize over a century of research on the adaptive significance of gender variation in plants. I place particular emphasis on the repeated evolution of gynodioecy and dioecy, the stability and maintenance of these two sexual systems, and the important role of phenotypic plasticity in transitions between them. Dioecy (=gonochorism) is the predominant sexual system in the animal kingdom, far exceeding any other, while gynodioecy is almost unheard of among animals. In plants, gynodioecy and dioecy are both relatively common and frequently derived, often co-occurring within plant genera. Perspectives on dioecy as a recently derived state can improve understanding of its adaptive significance. To do so in a broad context that allows for cross-kingdom comparisons, I address how predominant theories of the evolution of dioecy might be applied uniquely to plants vs. applied generally across eukaryotes.